What is HVAC?
HVAC stands for heating, ventilation and air conditioning. Even refrigeration “R” is sometimes applied and it becomes “HVACR”. HVAC employs to control the climate of confined indoor space with respect to the requirements of persons or goods in it.
HVAC is not only an ambient heating and cooling system but also an indoor air quality (IAQ) marinating system. Atmospheric heating is usually done in winter and air cooling is done in the summer season in the same way.
What is HVAC system?
The HVAC system is an assembly of various types of equipment built together to provide heating and cooling with indoor climate control. HVAC systems provide mechanical, electrical and I&C components for providing comfort to building/space occupants or for preserving space-placed objects, products or things.
HVAC cooling systems can be combined with or mounted separately depending on the design of the HVAC. HVAC system also used in the industrial manufacturing sector to keep the machinery running by maintaining the operating temperature of the machineries.
HVAC systems are used in household, building, industry, vehicles, aquariums and many more for heating and cooling & air conditioning. With the passage of time HVAC application is increasing and more research is in progress in this field.
Components of HVAC system:
An HVAC system includes such basic components:
- HVAC water chillers and heaters
- Hot water generator (if chiller does produce chilled water only) or furnace
- Chilled water pumps
- Cooling water pumps
- Electrical power supply control or Motor control center (MCC)
- Cooling towers
- Piping for chilled water and cooling water or condenser side water
- Valves for chilled water and cooling watersides
- Air handling units (AHUs) , heating coils and cooling Coils
- Ducts in ventilation system
- Fan Coil Units (FCUs) and thermostats
- HVAC Diffusers and grills
- HVAC controls (instrumentation & Control components) installed at various locations
- HVAC Control and Building Management System (BMS) building technology.
- An Assembly of all the above components forms an HVAC system.
Working of HVAC system:
In the context of the HVAC system, an HVAC water chiller creates chilled water that is then circulated throughout the building or space up to cooling coils in air handling systems.
Blowers transfer air on cooling coils that are then distributed in different parts of space or building to provide comfort or conserve goods / items as per HVAC model.
With the support of return ducts, air is pumped through supply ducts and return air is stored in air handling systems. Chilled water and cooling water pumps provide energy to keep the cooling water flowing.
HVAC Valves are also installed at different points in the piping to facilitate the maintenance of the HVAC system or to control the system. Air heating can be done with the help of the HVAC heat pump, hot water generator or simply by the furnace. Some industrial chillers also serve as heaters in the winter season.
During heating mode, heating coils take the place of cooling coils.
Types of HVAC system:
Different types of air conditioning systems (also known as types of HVAC systems) have been developed in the most economical and energy-efficient way to meet HVAC demands in various applications.
Air conditioning systems can be categorized as the following based on their size, design and operating characteristics
Individual Air conditioning System
An individual room or air conditioning system normally uses either a single, self-contained, sealed room air conditioner (installed in a window or through a wall) or separate indoor and outdoor systems to service a single room (split air conditioner) in the figure above you can see a split air conditioner.
Space Air conditioning System:
Such air conditioning systems have traditionally performed their air conditioning — cooling, heating and filtration — in or above the air conditioning room.
Packaged Air conditioning System:
Such air conditioning systems are equipped with either a single self-contained, factory-assembled packaged unit (PU) or two split units: an indoor air handler, typically with ductwork, and an outdoor condensing unit with compressor(s) and condenser for cooling.
In a packaged device, air is primarily cooled by direct coolant expansion within coils called DX coils and heated by gas furnace, electrical heating, or heat pump effect, which is the reverse of a cooling cycle.
Central Air conditioning System:
In a central hvac system, a central air conditioning system uses cold water and hot water from a central plant to cool and heat the air in the air handling unit (AHU) coils. The heat capacity of water for energy transport is about 3400 times higher than that of air. Central systems were manufactured and mounted on-site built-up structures.